In recent years, with the increasing pixels in digital cameras and digital camcorders, CCD structures and CMOS structures are becoming smaller in their cell size. However, when the cell size becomes minutely small, the reduced geometric area in which light is received leads to a decrease in the amount of light received by each pixel, which is a problem.
Patent Document 1 discloses an imaging device which uses, instead of color filters, spectroscopic sections that achieve color separation of light through diffraction, thus enhancing the efficiency of light utility and obtaining a color image. Patent Document 2 discloses a signal processing method which detects incident light via color separation using spectroscopic sections such as those indicated in Patent Document 1, thus obtaining a color image. By realizing such an imaging device, presumably a higher efficiency of light utility than that provided by conventional imaging devices using color filters is obtained. In the present specification, a color image is meant as an image whose color tone is expressed in two or more colors.